Process of producing motor fuel from hydrocarbon oils



Dec. 18, 1934. M CHAPPELL 1,984,519

PROCESS OF' PRODUCING MOTOR FUEL FROM HYDROCARBON OILS Filed May 17, 1932 IVE/475R INVENTOR WAOW cracking and reforming, a motor fuel with high Patented Dec. 18, 1934 PAT N )i PROCESS OF PRODUCING MOTOR FL FROM HYDROCARBON OILS Marvin L. Chappell, Watson, Calif.

' Application May 17, 1932, Serial No. 611,789

6 Claims. (Cl. 196-65) This invention relates to an improved method of processing hydrocarbon oils, such as naphtha, lamp oil distillates, gas oil stock, or other petroleum oil, to produce by partial dehydrogenation,

anti-detonating characteristics, and one which may be mixed or blended with other gasoline stocks to improve the anti-detonating characteristics thereof.

Briefly stated, my invention comprises passing hydrocarbon oil through a heating zone under superatmospheric pressure and heating the hydrocarbon oil to an elevated cracking temperature, then reducing the pressure sufficiently to permit vaporization of the hydrocarbon oil, and passing the vaporized oil into a reaction zone; mixing the vaporized oil in the reaction zone with a heated aeriform fluid containing from 5 to approximately 18 per cent by volume oxygen, in quantities sufficient to reduce the hydrogen content of the oil to approximately 14.3 per cent by weight or lower; and producing, by cracking and reforming, oils of the carbocyclic series, such as mixtures of hexahydrobenzol, hexahydrotoluol, hexahydroxylol, benzol, toluol, xylol, etc., which are oils having anti-detonating characteristics when used as a motor fuel.

Processesof producing oils such as benzol,toluol, xylol, etc., by a partial combustion or dehydrogenation of hydrocarbon oils with air or in the presence of air at elevated temperatures, are known in the art, such as described in U. S. Patents 1,214,204 and 1,257,906, granted to Frederick W. Mann and Marvin L. Chappell, dated January 30, 1917 and February 26, 1918 respectively, in which aromatic bodies and gas are produced by passing hydrocarbon oil and air through a highly heated zone filled with contact .material, at a pressure less than atmospheric. Similar processes are also known for the production of motor fuel by a partial combustion of hydrocarbon oil with air at elevated temperatures, under atmospheric or superatmospheric pressure. By such processes, however, high losses are sustained due to the intensity of the oxidizing reaction or partial combustion of the oil being processed, resulting in excessive formation of carbon and gas, which may be as much as 40-50 per cent of the hydrocarbon oil. I

Now, I have discovered that these excessive losses due to the partial conversion of the hydrocarbon oil into carbon and gases by known processes employing air, are principally due to the aeriform fluid containing too high an oxygen concentration; that by the employment of an aeriform fluid containing less than 18 per cent by volume oxygen the time of the oxidizing reaction may be prolonged and modified to prevent to a high extent violent molecular disruption of the oil, and thereby decrease the formation of carbon and gaseous products.

By this invention a heated aeriform fluid, having an oxygen content ranging from 5 to approximately 18 per cent by volume, is introduced with hot oil vapor into a contact reaction chamber, at a reaction temperature ranging from approximately 800 to 1300 degrees F., in quantities suflicient to reduce the hydrogen content of the oil vapor to approximately 14.3 per cent by weight or lower, the extent of dehydrogenation depending upon the hydrogen content of the oil treated and the products desired. For example, if it is desired to produce a motor fuel having an anti-knock value or octane number of .say 73, an aeriform fluid having an oxygen content of say 10 per cent by volume would be introduced in quantities sufllcient to reduce the hydrogen content of the oil to approximately 13 to 14.3 per cent, and a temperature would be maintained in the reaction chamber ranging from approximately 800 to 1100 degrees F.

If a motor 'fuel is desired having an octane number of say to 90, the quantity of aeriform fluid introduced, having an oxygen concentration of say 10 per cent, would be sufficient to reduce the hydrogen content of the oil to approximately 9 to 12 per cent, and the temperature maintained in the reaction chamber would be from approximately 1100 to 1300 degrees F.

The aeriform fluid employed may be air diluted with products of combustion, nitrogen, carbondioxide, carbon-monoxide, or other like gases, and the oxygen concentration is varied depending upon the percentage of hydrogen contained by the oil being processed and the products desired. For example, if the oil to be processed has an average hydrogen content of say 16 per cent by weight, the oxygen concentration of the aeriform fluid would be maintained at approximately 17 per cent by volume, and for an oil having a hydrogen content of 14 to 15 per cent, an oxygen concentration of approximately 10 per cent by volume would be used.

An object of the invention is to produce a motor fuel suitable for use in internal combustion engines with a high compression ratio, without requiring the use of anti-knock compounds such as tetraethyl lead.

Another object of the invention is to provide a continuous system for producing motor fuel with high anti-detonating characteristics, and then utilizing the motor fuel produced to blend with other gasoline or motor fuel stocks lower in anti-knock value to improve the anti-detonating characteristics thereof.

Another object of the invention is to provide a process which may be regulated to produce motor fuel of variable range in anti-knock values.

Various other objects and advantages of the present invention will be apparent from the description of the preferred form or example of the process embodying the present invention. For this purpose reference is made to the accompanying drawing, in which there is illustrated a form of apparatus in which the invention may be performed. The drawing represents a diagrammatical view of apparatus in which the parts are in sectional elevation.

In the drawing, 3 represents generally a tank for holding the hydrocarbon oil to be processed. Pipe 1, controlled by valve 2, connects tank 3 to a source of the hydrocarbon oil supply. Pipe 4, controlled by valve 5, connects tank 3 near the bottom to the suction side of pump 6. Pipe 7 connects the discharge side of pump 6 to heat exchanger 8.

Pipe 9 connects heat exchanger 8 to heater coil 11. Heater coil 11 is stationed in the upper section of heater or furnace 10. Heater or fur nace 10 is provided with an oil or gas burner 12. Pipe 13, controlled by valve 14, connects heater coil 11 to reaction chamber 15. The upper section of reaction chamber 15 is shown filled with contact material 16, such as checker brick work or hollow tile, supported by an arch 17, although an open reaction chamber without contact material may be employed. Reaction chamber 15 is preferably lined with a fire resisting material, as shown by the numeral 18, which may be fire brick, fire resistingcement, or other suitable furnace lining known in the art. I

Pipe 19 connects reaction chamber 15 at the top to heat exchanger 8. Pipe 20, controlled by valve 21, connects heat exchanger 8 to fractionat ing tower 22. Fractionating tower 22 is provided with bubble trays 23. Pipe 25, controlled by valve 24, connects fractionating tower 22 at the bottom to residuum tank 26. Pipe 27, controlled by valve 28, connects residuum tank 26 at the bottom to a storage not shown.

Pipe 29 connects fractionating tower 22 at the top to condenser coil 31. Condenser coil '31 is stationed in condenser box 30. Pipe 32 connects condenser coil 31 to gas separator 33. Pipe; 34, controlled by valve 35, connects gas separator 33 to a gas storage tank not shown. Pipe 36 connects gas separator 33 to a gasoline or,motor fuel storage tank 37. Pipe 38, controlled by valve 39, connects gasoline storage tank 37 at the bottom to a storage not shown.

Pipe 40 is connected to flues 52 and 53. Pipe 41, controlled by valve 42, connects pipe 40 to the inlet of pump 45. Pipe 43, controlled by valve 44, connects pipe 41 to a source of atmospheric air, and also to a source of nitrogen gas, carbondioxide or carbon-monoxide, through branch pipe 60 controlled by valve 61. Pipe 46 connects the discharge side of pump to heater coil 48-. Heater coil 48 is stationed in the upper section of heater or furnace 47. Heater or furnace 47 is provided with an oil or gas burner 49. Pipe 50, controlled by valve 51, connects heater coil 48 to the lower section of reaction chamber 15.

The preferred process as carried out in the apparatus just described is as follows:

Hydrocarbon oil, such as naphtha, lamp oil distillates or gas oil stock, contained in tank 3, is caused to flow through pipe 4 and into the suction side of pump 6, the rate of flow being governed by operation of valve 5. Pump 6 discharges the hydrocarbon oil to be processed in a regulated stream flow, under a pressure which may range from approximately 100 pounds to as high as 1000 pounds gauge or higher, through pipe 7, heat exchanger 8, pipe 9, heater coil 11, pipe 13, and into reaction chamber 15. The pressure maintained on the oil passing through heater coil 11 is controlled by pressure regulating valve 14.

The oil passing through heater coil 11 is heated to an oxidizing reaction temperature, that is, to a temperature where rapid oxidation may be effected without molecular disruption when mixed with an aeriform fluid containing from 5 to 17 per cent by volume oxygen. The temperature employed to heat the oil being processed preferably ranges from approximately 800 to 1300 degrees F., depending upon the stock treated and products desired.

The pressure on the heated oil stream is reduced to approximately 50 to 300 pounds or less, as it passes through pressure regulating valve 14, the exact reduction in pressure depending upon the boiling range of the oil and the temperature to which it is heated. For oils with relatively high boiling ranges, such as gas oil distillate, a pressure of 50 pounds gauge or less may be maintained in the reaction chamber 15, controlled by valve 21, while a pressure of 100 to 300 pounds may be employed in the reaction chamber 15 when certain grades of naphtha are being processed to increase the anti-detonating characteristics thereof.

In reaction chamber 15 the vaporized oil is mixed with an aeriform fluid containing, as heretofore stated, from 5 to 17 per cent by volume oxygen, which has been heated to a temperature ranging from 800 to 1300 degrees F., and in quantities sufficient to reduce the hydrogen content of the oil to approximately 14.3 per cent by weight, or less. The volume of aeriform fluid employed varies through a wide range, depending upon the grade and chemical composition of the oil to be processed.

For example, certain naphtha stocks derived from paraffin base crude petroleum oil, consisting principally of hydrocarbons of the paraffin series (CnH2n+2), may require as much as 300 cubic feet of the aeriform fluid (calculated at 0 degrees C. and 760 mm. pressure) containing say, 17 per cent by volume oxygen, per gallon of stock, to produce a motor fuel or gasoline stock having an octane number of 80 to 90. For certain distillates derived from an asphalt base crude petroleum oil, as little as 10 cubic feet of the aeriform fluid, containing from 5 to 17 per cent by volume oxygen, per gallon of stock, may be used to produce a motor fuel or gasoline stock with an octane number ranging from 70 to 90.

Aeriform fluid or products of combustion from furnaces 10 and 47, containing from 5 to 17 per cent by volume oxygen, are caused to pass from flues 52 and 53 into pipe 40. From pipe 40 the flue gases pass through pipe 41 and then into the inlet side of pump 45, the rate of flow being regulated by operation of valve 42. By means of pipe 43 and branch pipe 60, controlled by valve 44 and valve 61 respectively, the oxygen content of the flue gases may be increased or decreased to obtain the required oxygen concentration for the oil that is being processed, pipe 43 being connected to a source of nitrogen gas, carbon-dioxide or like gases, and also to a source of atmospheric air. Pump 45 discharges the aeriform fluid, containing the required oxygen concentration, through pipe 46, heater coil 48, pipe 50 controlled by valve 51, and then into the lower section of reaction chamber 15, wherein it is mixed with the vaporized oil coming from heater coil 11 through pipe 13.

The aeriform fluid passing through heater coil 48 is heated to a temperature ranging from approximately 800 to 1300 degrees F. or higher, this temperature depending upon the temperature of the vaporized oil entering reaction chamber 15, which is so regulated that the resultant temperature of the mixed vaporized oil and heated aeriform fluid, after the exothermic heat of the oxidizing or dehydrogenation reaction has been added, will be approximately 800 to 1100 degrees F. for the production of a motor fuel or gasoline stock to have an octane number of approximately '70 to '75, and approximately 1100 to 1300 degrees F. if a motor fuel or gasoline stock having an octane number of, say, 85 to 90 is desired.

The oil vapor, mixed with the aeriform fluid,

passes up through contact material 16 in reaction chamber 15, wherein the oil is dehydrogenated to the required degree, cracked and reformed with the production of gaseous products, high boiling oils and a motor fuel having anti-detonating characteristics to the required degree. From reaction chamber 15 the products of the dehydrogenation, cracking and reforming reaction, and spent aeriform fluid, pass through pipe 19, heat exchanger 8, pipe 20, pressure relief valve 21 where the pressure may be reduced to approximately atmospheric, and then into the lower section of fractionating tower 22.

In fractionating tower 22 the higher boiling oils are separated by fractionation from the aeriform products and the motor fuel produced. The higher boiling oil separated in fractionating tower 22 passes through pipe 25, controlled by valve 24, and collects in residuum tank 26. The higher boiling oil which collects in tank 26 may be conducted to other storage not shown through pipe 2'1, controlled by valve 28, after which it may be distilled and the distillate returned to the system and processed for the further production of motor fuel or gasoline stock.

The gasoline or motor fuel produced in vapor form, mixed with the other gaseous products, passes from the top of fractionating tower 22 through pipe 29 and into condenser coil 31, which is stationed in condenser box 30. A cooling fluid, such as water or brine, flows through condenser box 30, whereby the major portion of the motor fuel is condensed to a liquid. From condenser coil -31 the condensed motor fuel and gaseous products pass through pipe 32 and into gas separator 33,,wherein the liquid motor fuel is sep arated from the gaseous products and passes through pipe 36, and is collected in tank 37.

The gaseous products, containing a certain percentage of the motor fuel, pass through pipe 34, controlled by valve 35, to an absorber not shown, wherein the motor fuel retained by the gaseous products is separated by absorption methods known in the art, and thereafter returned and mixed with the motor fuel or gasoline stock contained in tank 37. The motor fuel which collects in tank 3'7 is conveyed to other storage not shown by pipe 38, controlled by valve 39,

and may be thereafter treated by known purification methods to produce a water white gasoline or motor fuel oil stock with high anti-detonating characteristics, or it may be blended with other gasoline stocks to increase the anti-detonating characteristics, as heretofore stated.

While the process herein described is well adapted for carrying out the objects of the present invention, it is to be understood that various modifications and changes may bemade without departing from the spirit of the invention, such, for example, as the use of other forms of elongated heaters or reaction chambers, and the invention includes all such modifications and changes as come within the scope of the appended claims.

I claim:

1. The process of dehydrogenation of petroleum oil, comprising the step of combining therewith aeriform fluid having a free oxygen content from to approximately 18 per cent by volume, in quantities sufficient to' reduce the hydrogen content of the oil to at least 14.3 per cent and to not less than 9 per cent by weight, at temperatures ranging from approximately 800 to 1300 F.

2. The process of dehydrogenation of petroleum oil, comprising the step of combining therewith air, mixed with an inert gas in amounts suflicient to reduce the free oxygen, content of the mixture to less than 18 per cent and to not below 5 per cent by volume, in quantities suflicient to reduce the hydrogen content of the oil to at least 14.3 per cent and to not less than 9 per cent by weight, at temperatures ranging from approximately 800 to 1300" F.

3. Improving the antidetonating qualities of hydrocarbon oils suitable for use as a motor fuel by contacting such hydrocarbon oil, at temperatures between 800 and 1300 F., with a gaseous mixture having a free oxygen content from 5 to approximately 18 per cent by volume, in quantities sufllcient to reduce the hydrogen content of the oil to at least 14.3 per cent and to notless than 9 per cent by weight.

4. In the method of dehydrogenating, cracking and reforming hydrocarbon oil to produce motor fuel or gasoline stock with antidetonating characteristics, the improvement which comprises, mixing heated vaporized hydrocarbon oil with a heated aeriform fluid containing from 5 to 17 per cent by volume free oxygen, in quantities sufficient to reduce the hydrogen content of the hydrocarbon oil to at least 14.3 per cent and to not less than 9 per cent by weight, then passing the mixed heated hydrocarbon oil vapor and aeriform fluid through a reaction zone at a reaction temperature of 800 to 1300 F., and separating motor fuel or gasoline stock from products of reaction and aeriform fluid.

5. In the method of dehydrogenating, cracking and reforming hydrocarbon oil containing hydrocarbons of the paraffin series to produce motor fuel or'gasoline stock containing a high percentage of hydrocarbons of the carbocyclic series, the improvement which comprises, heating the hydrocarbon oil under superatmospheric pressure to a temperature of 800 to 1300 F., reducing the pressure and vaporizing the heated hydrocarbon oil, mixing the vaporized heated hydrocarbon oil with a heated aeriform fiuid containing from 5 to 17 per cent by volume free oxygen, in quantities suflicient to reduce the hydrogen content of the hydrocarbon oil to at least 14.3 per cent and to not less than 9 per cent by weight, then passing the mixed heated hydrocarbon oil vapor and aeriform fluid through a reaction zone the vaporized oil in the vaporizing zone with a heatedaeritorm fluid containing approximately 10 per cent by 'volume free oxygen gas, in quantities sumcient to reduce the hydrogen content of the hydrocarbon oil to at least 14.3 per cent and to not less than 9 per cent by weight, passing the mixture of vaporized oil and aeriiorm fluid through a reaction zone at temperatures ranging from 800 to 1300 F., and finally separating a motor fuel or gasoline stock from products 10 of reaction and aeriform fluid.

MARVIN L. CHAPPELL. 

